Date: Fri, 17 May 2002 08:32:39 -0700 (PDT) From: Reinier Bezuidenhout <rbezuide@yahoo.com> To: freebsd-hackers@freebsd.org Cc: freebsd-emulation@freebsd.org Subject: Patches for linprocfs and linux emulation - fix 'ls /proc' bug and ipc's Message-ID: <20020517153239.98228.qmail@web11104.mail.yahoo.com>
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--0-1667895946-1021649559=:97425 Content-Type: text/plain; charset=us-ascii Hi all I have an application that uses the linux procfs extensively and also linux ipcs. I found two problems in the current linux emulation. (I hope the diff provided below will work as is since my mailing program is a bit limited :) ) 1) linux_ipc.c has a pice of code commented that we can actually use now. I think the other pieces were added later and this didn't get changed. The patch is valid for RELENG_4 and HEAD. The current code will always remove only the first enry from a msg queue even if msgtyp was specified causing incorrect behaviour. It's a one line change in linux_ipc.c in src/sys/compat/linux 2) When traversing the linprocfs with i.e. ls (the linux ls in /compat/linux/bin/ls ) I noticed that some entries in the proc table is missing, compared to doing a FreeBSD ls /bin/ls. I traced the problem to a counter inconcistenct because linux reads smaller blocks at a time. This problem is only in RELENG_4 and not HEAD since the linprocfs changed a lot in HEAD. The loop skips the first 9 entries for the cpuinfo etc. in /compat/linux/proc, but on the second loop it skips the first 9 entries in the proc table and thus they do not show up in a /compat/linux/bin/ls If someone responsible from the linux emulation can review these changes and maybe commit them, I'll appreciate it :) Thanks Reinier ------------------------ cut -------------------- cut ----------------------------- *** linprocfs_vnops.c 2001/08/12 14:29:19 1.3.2.5 --- linprocfs_vnops.c 2002/05/17 15:19:43 *************** *** 896,902 **** default: ! while (pcnt < i) { p = p->p_list.le_next; if (!p) goto done; --- 896,907 ---- default: ! /* Since we skip the first 9, by the time we ! * get here i = 9 and we'll end up skipping ! * the first 9 procs in the list, so we ! * increment pcnt by the same value ! */ ! while ((pcnt + 9) < i) { p = p->p_list.le_next; if (!p) goto done; ----------------- cut -------------- cut ------------------ cut ---------------- *** linux_ipc.c.old Fri May 17 11:08:58 2002 --- linux_ipc.c Fri May 17 11:09:29 2002 *************** *** 358,364 **** bsd_args.msqid = args->msqid; bsd_args.msgp = args->msgp; bsd_args.msgsz = args->msgsz; ! bsd_args.msgtyp = 0; /* XXX - args->msgtyp; */ bsd_args.msgflg = args->msgflg; return msgrcv(td, &bsd_args); } --- 358,364 ---- bsd_args.msqid = args->msqid; bsd_args.msgp = args->msgp; bsd_args.msgsz = args->msgsz; ! bsd_args.msgtyp = args->msgtyp; bsd_args.msgflg = args->msgflg; return msgrcv(td, &bsd_args); } ----------------- cut ---------------- cut -------------- cut ----------------- --------------------------------- Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience --0-1667895946-1021649559=:97425 Content-Type: text/html; charset=us-ascii <P>Hi all</P> <P>I have an application that uses the linux procfs extensively and also linux ipcs. I found two problems in the current linux emulation. </P> <P>(I hope the diff provided below will work as is since my mailing program is a bit limited :) )</P> <P>1) linux_ipc.c has a pice of code commented that we can actually use now. I think the other pieces were added later and this didn't get changed. The patch is valid for RELENG_4 and HEAD. The current code will always remove only the first enry from a msg queue even if msgtyp was specified causing incorrect behaviour. It's a one line change in linux_ipc.c in src/sys/compat/linux</P> <P>2) When traversing the linprocfs with i.e. ls (the linux ls in /compat/linux/bin/ls ) I noticed that some entries in the proc table is missing, compared to doing a FreeBSD ls /bin/ls. I traced the problem to a counter inconcistenct because linux reads smaller blocks at a time. This problem is only in RELENG_4 and not HEAD since the linprocfs changed a lot in HEAD. The loop skips the first 9 entries for the cpuinfo etc. in /compat/linux/proc, but on the second loop it skips the first 9 entries in the proc table and thus they do not show up in a /compat/linux/bin/ls</P> <P>If someone responsible from the linux emulation can review these changes and maybe commit them, I'll appreciate it :)</P> <P>Thanks </P> <P>Reinier</P> <P> </P> <P>------------------------ cut -------------------- cut -----------------------------</P> <P>*** linprocfs_vnops.c 2001/08/12 14:29:19 1.3.2.5<BR>--- linprocfs_vnops.c 2002/05/17 15:19:43<BR>***************<BR>*** 896,902 ****<BR> <BR> <BR> default:<BR>! while (pcnt < i) {<BR> p = p->p_list.le_next;<BR> if (!p)<BR> goto done;<BR>--- 896,907 ----<BR> <BR> <BR> default:<BR>! /* Since we skip the first 9, by the time we<BR>! * get here i = 9 and we'll end up skipping <BR>! * the first 9 procs in the list, so we<BR>! * increment pcnt by the same value<BR>! */<BR>! while ((pcnt + 9) < i) {<BR> p = p->p_list.le_next;<BR> if (!p)<BR> goto done;<BR></P> <P>----------------- cut -------------- cut ------------------ cut ----------------</P> <P>*** linux_ipc.c.old Fri May 17 11:08:58 2002<BR>--- linux_ipc.c Fri May 17 11:09:29 2002<BR>***************<BR>*** 358,364 ****<BR> bsd_args.msqid = args->msqid;<BR> bsd_args.msgp = args->msgp;<BR> bsd_args.msgsz = args->msgsz;<BR>! bsd_args.msgtyp = 0; /* XXX - args->msgtyp; */<BR> bsd_args.msgflg = args->msgflg;<BR> return msgrcv(td, &bsd_args);<BR> }<BR>--- 358,364 ----<BR> bsd_args.msqid = args->msqid;<BR> bsd_args.msgp = args->msgp;<BR> bsd_args.msgsz = args->msgsz;<BR>! bsd_args.msgtyp = args->msgtyp;<BR> bsd_args.msgflg = args->msgflg;<BR> return msgrcv(td, &bsd_args);<BR> }<BR></P> <P>----------------- cut ---------------- cut -------------- cut -----------------</P><p><br><hr size=1><b>Do You Yahoo!?</b><br> <a href="http://rd.yahoo.com/welcome/*http://launch.yahoo.com">LAUNCH</a> - Your Yahoo! 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